Tuesday, March 16, 2010

Racing has Started 2010

I've had an interesting start to the new season. Normally, I'd hit a bunch of climbing races. This time, I've done five flat races, three on my TT bike. I opened with Beat the Clock (a training series) and beat my old best time by ~30 s. Not as much as I would've expected given the supposed slipperiness of my TT bike. Keep that thought in mind. The following weekend, I did the Berkeley TTT. It was a bit longer, but it didn't feel as hard as Beat the Clock. We had a mechanical on course, but still finished 3rd out of 6. I'll take that for now.

The Madera Stage Race was this past weekend. We got luxurious start times, and I rolled to the TT course with hours to spare. It was very windy and very cold for us soft northern Californians. I decided to go with a disc in the rear despite the risk of being blown off course. I had a very good race pacing and power-wise, setting new power records from 20 min on to the end of the race. Unfortunately, as the BtC result showed, I'm not aero. I killed it into the headwind and still lost time. A good point to work on for the future, and relatively simple compared to fitness, I hope. It's something you can throw money at, after all. Next up was the crit. Mind you, I haven't done a crit in four years, and have maybe done four ever. The wind was howling. I was surfing around near the back just trying to remember how to sit in a pack when the prime bell rang. OK, go faster. Then the field split when I rotated toward the back and someone smartly countered after the prime lap. I surged past the pack from the rear and bridged solo to the break. Unfortunately, the break had already split so I was now in the chase. Drilled it for another 40 minutes and lost 53 sec on the break, but at least made a decent move for my first crit back. The next day was the RR. Not too hard, but had to go to the bathroom incredibly badly. Need to learn to pee while riding; I've been told it's an art form. DNF. Next up are some hillier road races where my weight might actually be an advantage for a change!

Sunday, January 24, 2010

Back at it

Back in November, I was honored to be selected for the John E. Peckham Memorial Scholarship. Since then, I've been training much more consistently, especially for winter. I'm really looking forward to this season, and figured I'd go all in. So I got a TT bike:

TT bike

And have been riding a bunch in the NorCal rain, which was fairly drenching over the past few days. I think I'm going to open up with a TTT in February, but might do a MTB race just for fun this coming weekend. For now, I'm happy to dial in my pedaling technique and get more comfortable riding in inclement weather while building my fitness.

Post wet ride

Things I really like now:
25mm tires
Gore-Tex jackets and gloves
Rain bikes

Sunday, November 8, 2009

Quarq Accuracy

I've ridden one stretch of road enough to try to see how repeatable the Quarq CinQo is. It's the stretch from the bottom of Montebello to the school. So, we can play some games with numbers. Let's assume that I didn't change wheels (I probably put a set on that weighs ~1/2 lb lighter for some runs) and that my body weight and clothes were constant. Here are the results:

timeaverage powerdeviationkJ

So, the mean is 237.5 kJ, and I've tabulated the deviation from this. It looks like the Quarq is well within its +/-2% accuracy spec, but of course, this spans a lot of time and probably many variations in weight and equipment. Oh yeah, I'm neglecting the confidence in the mean and such things that probably matter. I'm basically impressed that a device as rugged as this can give such repeatable data day after day.

OK, enough geeking out for a day.

Tuesday, September 1, 2009

Coast down estimation of drag and rolling resistance - Part 1

So I promised some geekery here. The goal was to do a simple test and try to estimate rolling resistance and drag coefficients. The simplest thing anyone can do is a coast down: you accelerate to speed, stop pedaling, and coast to a halt (or close to it.) So, to do the analysis, you first need to solve the equation that describes the motion:

ρ is the density of air
crr is the coefficient of rolling resistance
CdA is the drag coefficient multiplied by the frontal area of bike and rider
m is the mass of rider and bike
g is the acceleration due to gravity
v is the velocity of rider and bike

You can use separation of variables to get a rather gnarly looking expression that describes the coast down behavior of a rider in a constant position:

where I've defined:

I went out and did several coast-down tests in two positions (straight arm in drops, hands on tops,) and covering the same course forward and backward. The reason for this is that and slope will look like a change in rolling resistance, so if you take the average rolling resistance derived from the two directions, that should cancel out any error due to slope. It does NOT cancel out wind, so I did this at midnight, which is typically fairly wind-free. I downloaded the data from the powertap and used the nonlinear fitting function in Excel (blah :() to find values for crr, CdA and t0. I then used R to see if there was a statistical difference in rolling resistance and drag between the two positions I used, and to estimate the error in those values. Next time, I'll show some data.

Monday, August 31, 2009

Teetering on the edge

One of the challenges of training is getting close to the edge, but not falling off. The human body has a strange negative feedback mechanism. Do too much physical work and you have problems sleeping, and you slow down, making you think you have to do more work to compensate. I've overtrained before, but this year I've been pretty good (so far) at walking up to that edge and not going over it. This weekend was pretty close to it for me; after riding ~5 hours in 105 degree weather with a bunch of climbs on Saturday and three times up Mt Diablo on Sunday, I'm due for some rest.

Monday, August 24, 2009

A Rarity

My wife came with me to the race. It's probably the only road race worth going to to watch the race, though there may be others in cool places to visit. She grabbed this photo of me:

So I don't just make up stories about riding...

University Road Race

Ah, University. As a simpleton racer, this is a race I can actually train for. It goes up, then it goes down. I usually like that kind of thing. Things started in earnest, with Menso de Jong rolling off the front repeatedly, and Chris marking him early on in the race. The pack reeled them in several times before Menso finally broke the elastic and rode away from everyone in true pro MTBer style. Chris followed after him, but got reeled back in one last time. Somehow, I managed to remember to drink without him there to remind me, but from now on I'm gonna have "god, do I have to mother you?" stuck in my head in Chris's voice.

Like I said, I'm simple racer, so I followed some simple rules for the rest of the race: coast up to the front on the descent, drift back on the climb, and never stand on the kicker unless absolutely necessary. I closed gaps where necessary as attrition really set in after 10 laps, but basically sat in pretty comfortably thanks to all the work Chris was doing off the front.

With only Menso long gone off the front for the last few remaining laps, not too much was going on in the pack. I managed to drop my chain and had to do a pretty hard effort to chase back on, but even that was fairly uneventful. I repeated my simple plan and thought about what I was going to try to do on the last lap. Somehow, I got it in my head that it would be a fantastic idea to launch a sprint from the corner, about 2 minutes from the finish line. Unfortunately, a rider from Cyclepath had already cleared the group by the last corner when I wasn't paying attention, so it was a race for third. I attacked hard up the left side right after the corner, looked Chester from Platinum square in the eye and we were off. I led out for the last 1.5 min, then Chester came around me for 3rd near the line; I held my position for 4th. We almost caught the Cyclepath guy, so I can't say I made the wrong choice, just not the best. Glad I was able to hold on for so long given my early "sprint" start!

I stuck around to cheer on the 4/5 and women's fields, then had a great lunch in SC before heading home.

Legs are finally coming around, so I'm looking forward to at least Challenge and Everest later on this year.